1. Field of the Invention
This invention relates to an image forming apparatus such as an electronic photography type copying machine or printer for obtaining an image by means of an endless transfer belt that has a cleaning member for cleaning the surface of a transfer belt after a transfer operation.
2. Description of the Related Art
Tandem type image forming apparatus comprising a plurality of image forming units having respective photosensitive members and arranged in parallel and an endless intermediate transfer belt are known. In a tandem type image forming apparatus, the toner images formed on the respective photosensitive members are firstly transferred onto the endless intermediate transfer belt one on the other to form a single color toner image as primary transfer, which color image is then transferred onto a recording medium to produce a final color image as secondary transfer. Some tandem type image forming apparatus are equipped with a cleaning apparatus adapted to be brought into contact with the intermediate transfer belt and moved away from the latter. For example, Jpn. Pat. Publication (Kokai) No. 2001-255750 discloses such an apparatus.
In known such apparatus, a blade member is provided so as to be brought into contact with the intermediate transfer belt and moved away from the latter as an operation lever is turned. In recent years, there has been a demand for apparatus equipped with a removable cleaning apparatus that can be replaced independently relative to the intermediate transfer belt because the cleaning apparatus is in need of frequent maintenance. Such removable cleaning apparatus are required to be replaceable with ease without damaging the intermediate transfer belt.
Additionally, among tandem type image forming apparatus of the type under consideration, there are some in which the intermediate transfer belt cleaning apparatus is removably mounted in the apparatus main body. For example, Jpn. Pat. Publication (Kokai) No.2005-181820 and Jpn. Pat. Publication (Kokai) No. 2003-316107 discloses such apparatus.
In those known apparatus, the intermediate transfer member and the intermediate transfer member cleaning apparatus are integrally unitized so as to be integrally and removably mounted in the apparatus main body. Then, an anchor member that anchors the intermediate transfer member and the cleaning apparatus to the main body has to be released to take out the cleaning apparatus when performing maintenance on the cleaning apparatus that requires relatively frequent maintenance. Thus, the replacing operation requires much labor. Such apparatus are far from easy maintenance. Otherwise, the intermediate transfer belt has to be taken out from the apparatus main body when only the cleaning apparatus requires maintenance. Because the intermediate transfer belt is rather heavy, then the apparatus is also far from easy maintenance.
Therefore, it is desirable to replace a cleaning member for cleaning the belt member that is independent from the belt member in a safe and easy manner for a tandem type image forming apparatus comprising a plurality of image forming units, so as to prevent the surrounding units from being tainted by toner and improve the maintenance capability.